Thermal meter



Ndv. 7, 1933. J. FISCHER 1,934,595

THERMAL METER Filed Dec. 1931 V in opposition, intoa-si-nglethermaleleetric n egsfeet r two of th devieesof Figure zv,

Fatented Nov. 7, 1933 I ohannes Fischer, Karlsruhe, GenmaQhy; -a ssignorr -toN. V. lnstrume'ntfabriek en-"lIandel .voqrheen;

' :s clai ms, C171. ie- 31 This inventionrelates toimprovementsinthermal metersespecially for use-for measuring prod.- netsof electrical quantities. of the tyne which works accordingto-theformula.

-N=EI='- T- [-'(-E-+'I)" -E J1?] the productjof the two quantities Eandlj being b d y utual ysubtrsct s the n spq se ofdevices, each of:whi'chgivesBJ RSPQ IS Q portional to the'square of one of the"quantities, that is to say,.o frthels nm"or difference of twoquantities, and which devices are thermal measurin dv ati ircuitsandi'hemeesuring' eircuits,of whic h. are so connected that the desiredproductis obtained in the measurin cir- 'cuit. v V

The invention also comprises meens tqmeasyre thesingle quantities withan mstrn' nent;of1'the type; described.

are connec'tedtogether in oppositiqn.

Another object of thei-nvention is;lto, eff (its 111- plifiedembodimentsof the main inven ,e 1

which are obtainedrliysuitably, combining qlfieru elndftheldad, 2. westAn object oftheinyention islto' pmyide, asla step in themenniaetnreoithese instrume tslan imp y d metheilidr efie'ctin adjus m n of thresponses) oi vthe ,individlielnther'mal elements. in v such mann nthatth undes red;cdmn i nt the electroiniot'oric forces1116116113131:ding'thesefelerments correctly balance outwhensnchelements mf e nventiqnrs o bftifi. 'ii iei n txumm t m ri s h eel heetingjw re A; 4. r conneced a sh wn, th Wis s: a d 9- w R011 im load. 1 nd: i'the w f meinsv liil se s i etw e .a 'i ififirlqpm xt em t ofa. 5 m .L thv l i x ml fi ofvwh his1 .0nn zfl tothe 1 1 9? ell-P9431 A 9 deaths W hthes. QQIHZQC.rnsr heid l tenti sp n the heating wir lfi-nesq rreet 'I ETQQW he? W rbeil aqqilsfiapfi lan he m uringdevicehavinga.pluraiitypiheetingwires.If v

tion, andv arran eme t. :of evice scribed and claimed;v r r.

"In the drawing e With'the above and other objects in,,v iew,- the 1'invention consistsrinthe censtrnction comb liw it rei eite Figure i'is adiagramlshowing the eonneetiens. I

of an instriiment of the type'describedsioivaalternatively-measuring theoltage, current strength Y and Wattage s uppliedby a genereten;

' Figure 2 is aperspectiveview of a '-'t-h rir1-e1- electric measuringdevice as 'useci' infthe nstrument, represented diagramr'netieailyF1gue;;1=.

Figure 3, aiperspecti l f a iihl rn measuring device, ,"whichgivesFigure 4 is a perspectiyeoin,

Figure-51151.5 ma -ramp QQ QHQQ Q zan instrumentiforssilnmteneeislywmeesurmg ill-e triple. {therm l .sme ur ne' -de i z -w iv ee a P l t9 m tion ora di-tien of ih e hermek H vices ascend n to F u e .easurin 1Eminent; e igfl ign I 'ifhis resu.ti T

-i ic ne tedi n series to io my q 'Q the COIIQQQ'JQITS betwe n there thethermal electric efiects in reach of the measuring conductors beingproportional to the square of the current in the correspondingheating-wire, the factorof proportionality being '0. J.

Similarly with the switch arm 19 in the position A, a measuring circuitwill be formed from one pole of the instrument 18, through conductingpiece 20 of switch arm 19, through 6,,conductingpiece 21 of switch arm19 backto the other pole of instrument 18. In this measuring circuit theelectromotive force developed in 10 acts on the measuring instrument;this'electromotiveforce being proportional to the square of the current,the measuring instrument indicates the current strength supplied by thegenerator 1.

Finally if the switch arm is on the contact V themeasuring instrument 18will givea deviation proportional to the electromotive force developedin '9. This electromotive force being i proportional to the square ofthe voltage," the a single instrument.

instrument 18. will now indicate the voltage.

As shown in Figure 3, a double thermal measuring'device having twoheating wires may be ;used insteadof two separate thermal measuringdevices each with a single heating wire. In this instance it has beenassumedthat the devices 5, 8 and 4, 9 of Figure 1 have been combinedinto In the actual'instrument' the wires 4 and 5 have of 'course to'beconnected conductors 8 and 9 of two separateithermal measuring devices,as supposed in the above description. To this end the polarities? ofsuccessive hot junctions 'heatedbythe two wires land 5 is chosen,so thatthe thermal electric forces developed in these .hotjunctions aresubtracted from each other. This is efiected "in "a simple wayas shownin the drawing by choosing the center portion of each strip from one of;the'metals constitutingthe thermaljunctions and the endv parts fro'mtheotherj metal.

threethermalmeasuring; devices into a triple Wires 5, 4 and 6. In orderto effect the subtraction .of the thermal effectsind uced by the heatingWires 4. and 6 froin' that induced by the heating wire '5 each thermalelectric strip lying over thethree heating wires is built'up fromsections of the constituent metals of the thermaljunction in the mannerindicated in'the figure, thereby forming three hot junctions in eachstrip, two of which,

flying onheating wires 4 and fijgiving electromov tive forces'in onedirection, while the thermal. electric force induced byheating wire 5 inthe third hotfjunction is in the. opposite direction.

-An instrument having thre'e indicating meters V, A,andWfforsimultaneously indicating a voltage, current strength and wattsrespectively is shown'diagrammatically in Figure 5 which corresponds toFigure lf' e'xoepting in the connections 3 of thethermalmeasuringconductors 8, 9 and 10.

' As shown in Figure 5 the thermal measuring. con-' ductors 9 and 10 areeach connected to am instrument, V and A respectively showing voltsandamps, the three measuring conductors 8,9 and 10 being connected inseries in the circuit of the wattrneter W, in such a manner, that thethermal electric forces developed in the conductors 9 and 10 are inopposition to that developed in conductor 8. :Switching means forconnecting or disconnecting each indicating instrument from the thermalelectric sources may be provided if desired. .-The invention is notlimited to the examples shown and described in the presentspecification, but what I claim is:

1., An'instrument for measuring products of electricalquantities, havingthree circuits joined in one point, inone of which circuits flows acurrent representing one of the said electrical quantities, in asecondof which circuits flows a current representing another suchquantity, and in the third a current representing a function of additionof the said quantities, said last circuit and at least one of the othercircuits containing heating wires with thermal measuring devices, the

sensitiveparts of which are so arranged that their effects aresubtracted from each other. 2'. An instrument for measuring products of.

electrical quantities, having three circuits joined in one point, in oneof, which circuits flows a current representingfone of the saidelectrical quantities, in asecond of which circuits flows a currentrepresenting anothersuch quantity, and in,

th'e'thirda current representing a function of addition of the saidquantities,'a ll three circuits containing heating wires with nthermo-junctions, at being a whole number, the eiTect of the I junctionsheated by thecurrents in the first men-. tioned two circuits beingsubtracted from that of the junction corresponding to the last mentionedcircuit.

3; An instrument for measuring .products of electrical quantities,having three circuits joined in one point, in one of which circuitsflows a current representing one of the said electrical quantities,whereas in a second circuit flows a current representing another suchquantity, and in the third'a current representing a function of additionof the said quantities, all three circuits containing heating wires withn thermo-junctionan being awhole number, the efiect of the junctionsheated by theburrentsi inthe first mentioned U r Ittvocircuits, beingsubtracted from that of the I A further simplification of theconnections is obtainedas shown in, Figure 4 by combining the junctioncorresponding to the last mentioned'cir- 'cuit, inherent errors beingcompensated by a change of the; response of the thermo-junctions.thermal measuring device, having three heating 4, An' instrument formeasuring products of electrical quantities, having three circuitsjoined in one point, in one of which circuits flows a currentrepresenting one of the said; electrical n being a whole number, thesensitive parts of which are so arranged that their effects aresubtracted from each other, an even number of thermal elements beingcombined into a thermoelectric measuring device having an even number ofjunctions so that the difference between 7 two of the quantities tobemeasured is obtained by a single measuring-device;

1 5. An instrument for measuring products of electrical' quantities,having three circuits joined in one -point,'in-'one of which-circuitsflows a current representing one of the said electrical quantities,-whereas. 'in a second circuit flows a current representing another suchquantity, and in the third a current representing a function of additionof the said quantities, all three circuits containing heating wires withn thermo-junctions, n being a whole number, the junctions forming asingle unit with an uneven number of junctions, these being so joinedthat the effect of the junctions heated by the currents in the firstmentioned two circuits is subtracted from that of the junctioncorresponding to the' last mentioned circuit.

6. An instrument for measuring 7 electrical quantities, as well as aproduct of these quantities, having three circuits joined in one point,in one of which circuits flows a current representing one of the saidelectrical quantities, whereas in a second circuit flows a currentrepresenting another such quantity and in the third a currentrepresenting a function of addition of the said quantities, this lastcircuit and at least one of the other circuits containing heating wireswith n thermal measuring devices 11. being a whole number, the sensitiveparts of which are so arranged that their effects are subtracted fromeach other, the result representing the required product, the quantitiesthemselves being represented by the responses of the individual thermalmeasuring devices.

7. An instrument for measuring electrical quantities, as well as aproduct of these quantities, having three circuits joined in one point,a first thermo-junction, heated by a heating wire in one of thesecircuits, this junction indicating in a'direct current measuringinstrument one of the said electrical quantities,'whereas the current ina second circuit heats a second set of n thermo-junctions which mayalternatively indicate in the said direct current measuring instrumentanother such quantity, and the current in the third circuit whichrepresents a function of addition of the said quantities, heats a thirdset of p thermo-junctions which alternatively indicate in conjunctionwith the two first mentioned sets of junctions in the said directcurrent measuring instrument the product of the said quantities, andswitching means for alternatively connecting the said junctions in thecorrect manner to the said instrument.

' 8. An instrument for measuring electrical quantities, as well as aproduct of these quantities, having three circuits joined in one point,a first set of n thermo-junctions, heated by a heating wire in one ofthese circuits, these junctions indicating in a first direct currentmeasuring instrument one of the said electrical quantities, whereas thecurrent in a second circuit heats a second set of m thermo-junctionswhich indicate in a second direct current measuring instrument anothersuch quantity, the current in the third circuit which represents afunction of addition of the said quantities'heating a third set of pthermo-junctions which indicate in conjunction with the two firstmentioned junctions in a third direct current measuring instrument theproduct of the said quantities.

J OHANN ES- FISCHER.

